Hypoglycaemic activity of four plant extracts traditionally used in South Africa for diabetes

Abstract

a b s t r a c tAim: To validate plant species for hypoglycaemic activity. Materials and methods: Four plants were investigated for hypoglycaemic activity by evaluating inhibiting effects on carbohydrate-hydrolising enzymes: ␣-glucosidase and ␣-amylase. Acetone plant extracts were screened against C2C12 myocytes, 3T3-L1 preadipocytes and Chang liver cells by measuring glucose uptake. Cytotoxicity was done in preadipocytes and hepatocytes. Results: Extract of Euclea undulata rootbark exhibited highest activity, displaying a glucose uptake of 162.2% by Chang liver cells at 50 g/ml. An inhibition concentration of 50% for Euclea undulata was found to be 49.95 g/ml for ␣-glucosidase and 2.8 g/ml for ␣-amylase. No cytotoxicity was recorded for Euclea undulata, while Schkuhria pinnata and Elaeodendron transvaalense exhibited cytotoxicity at 12.5 g/ml. ␣-Glucosidase and ␣-amylase assays showed inhibitory activity on enzymes for three plant extracts. Conclusion: Euclea undulata, Schkuhria pinnata and Elaeodendron transvaalense showed in vitro hypoglycaemic activity. Schkuhria pinnata and Elaeodendron transvaalense indicated cytotoxicity on 3T3-L1 preadipocytes and Chang liver cells. Euclea undulata, Pteronia divaricata and Elaeodendron transvaalense inhibited ␣-glucosidase and ␣-amylase enzymes. Ethnopharmacological relevance: Screening of plant extracts scientifically validated traditional use of Euclea undulata for treatment of diabetes. Cytotoxicity results revealed that acetone extracts of Schkuhria pinnata and Elaeodendron transvaalense are toxic and raise concern for chronic use.

Antidiabetic effects of natural plant extracts via inhibition of carbohydrate hydrolysis enzymes with emphasis on pancreatic alpha amylase

“…Despite that, some of the plants used in Africa to treat diabetes are able to inhibit intestinal alpha-amylase and glucosidase activities, such as Euclea undulata, Pteronia divaricata and Elaeodendron transvaalense (34) or Spondias mombin (35).…”

Hypoglycemic evaluation of a new triterpene and other compounds isolated from Euclea undulata Thunb. var. myrtina (Ebenaceae) root bark

“…This selection was based on the facts that the crude acetone extract of E. undulata root bark gave positive results (hypoglycaemic activity) in the in vitro assays done on C2C12 myocytes, 3T3-L1 preadipocytes and in Chang liver cells without displaying any toxicity and scored a +3 total score, according to the scoring system developed by Van de Venter et al (2008). The carbohydratehydrolysing enzymes alpha-amylase and alpha-glucosidase were also inhibited to some extent (Deutschländer et al, 2009). …”

Assessment of the Antidiabetic Potential of an Aqueous Extract of Honeybush (Cyclopia intermedia) in Streptozotocin and Obese Insulin Resistant Wistar Rats

“…On the African continent as many as 90% of the populations of some countries relies on plants as the principal source of medicine for the treatment of different diseases, including diabetes (Hostettman et al, 2000), as they provide an affordable alternative to drugs. In South Africa a large number of plants, belonging to plant families such as the Asteraceae and Lamiaceae, amongst others, have been traditionally used for the treatment of diabetes (Deutschländer et al, 2009;Erasto et al, 2005;Thring & Weitz, 2006).…”